transport.c::handshake: make use of server options from remote
Utilize the `server_options` from the corresponding remote during the
handshake in `transport.c` when Git protocol v2 is detected. This helps
initialize the `server_options` in `transport.h:transport` if no server
options are set for the transport (typically via `--server-option` or
`-o`).
While another potential place to incorporate server options from the
remote is in `transport.c:transport_get`, setting server options for a
transport using a protocol other than v2 could lead to unexpected errors
(see `transport.c:die_if_server_options`).
Relevant tests and documentation have been updated accordingly.
Signed-off-by: Xing Xin <xingxin.xx@bytedance.com> Reviewed-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>